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1.
Antony Joseph R. G. Prabhudesai Prakash Mehra V. Sanil Kumar K. V. Radhakrishnan Vijay Kumar K. Ashok Kumar Yogesh Agarwadekar U. G. Bhat Ryan Luis Pradhan Rivankar Blossom Viegas 《Natural Hazards》2011,57(2):293-312
Response of the coastal regions of eastern Arabian Sea (AS) and Kavaratti Island lagoon in the AS to the tropical cyclonic storm `Phyan??, which developed in winter in the south-eastern AS and swept northward along the eastern AS during 9?C12 November 2009 until its landfall at the northwest coast of India, is examined based on in situ and satellite-derived measurements. Wind was predominantly south/south-westerly and the maximum wind speed (U10) of ~16 m/s occurred at Kavaratti Island region followed by ~8 m/s at Dwarka (Gujarat) and ~7 m/s at Diu (located south of Dwarka) as well as two southwest Indian coastal locations (Mangalore and Malpe). All other west Indian coastal sites recorded maximum wind speed of ~5?C6 m/s. Gust factor (i.e., gust-to-speed ratio) during peak storm event was highly variable with respect to topography, with steep hilly stations (Karwar and Ratnagiri) and proximate thick and tall vegetation-rich site (Kochi) exhibiting large values (~6), whereas Island station (Kavaratti) exhibiting ~1 (indicating consistently steady wind). Rainfall in association with Phyan was temporally scattered, with the highest 24-h accumulated precipitation (~60 mm) at Karwar and ~45 mm at several other west Indian coastal sites. Impact of Phyan on the west Indian coastal regions was manifested in terms of intensified significant waves (~2.2 m at Karwar and Panaji), sea surface cooling (~5°C at Calicut), and moderate surge (~50 cm at Verem, Goa). The surface waves were south-westerly and the peak wave period (T p) shortened from ~10?C17 s to ~5?C10 s during Phyan, indicating their transition from the long-period `swell?? to the short-period `sea??. Reduction in the spread of the mean wave period (T z) from ~5?C10 s to a steady period of ~6 s was another manifestation of the influence of the cyclone on the surface wave field. Several factors such as (1) water piling-up at the coast supported by south/south-westerly wind and seaward flow of the excess water in the rivers due to heavy rains, (2) reduction of piling-up at the coast, supported by the upstream penetration of seawater into the rivers, and (3) possible interaction of upstream flow with river run-off, together resulted in the observed moderate surge at the west Indian coast. Despite the intense wind forcing, Kavaratti Island lagoon experienced insignificantly weak surge (~7 cm) because of lack of river influx and absence of a sufficiently large land boundary required for the generation and sustenance of wave/wind-driven water mass piling-up at the land?Csea interface. 相似文献
2.
从沉积速率和沉积物粒度看冰后期海侵以来珠江三角洲西江大鳌沙的形成 总被引：2，自引：2，他引：2
大鳌沙处于珠江三角洲西江河口的近口段，洪季西江河口的潮区界西线在其顶端附近。冰后期海侵以来，大鳌沙顶端的PRD05和中部的PRD04两个钻孔的沉积速率和沉积物粒度有着极大的差别。7 630 a BP以前，PRD04孔的沉积速率小于PRD05孔的沉积速率；但7 630 a BP以来，PRD04孔的沉积速率大于PRD05孔的沉积速率。从粒度分析看，埋深12.28 m以下，PRD04孔沉积物比PRD05孔的粗，分选性比PRD05孔的差；埋深12.28 m以上，PRD04孔的沉积物比PRD05孔的细，分选性相对比PRD05孔的好。分析表明，9 000～4 200a BP， 沉积物由南（中部）向北（顶部）输运，涨潮流冲蚀老沉积物，在喷出磨刀门通道后，流速迅速降低，粗颗粒泥沙先沉积，而细颗粒泥沙被涨潮流搬运至更北的区域沉积。近3500年以来，河流动力占优势，沉积物由北（顶部）向南（中部）输运。大鳌沙的形成与涨潮射流密切相关。涨潮射流口的位置在蛇地山和右岸纵向山地之间，宽约2200 m。 相似文献
3.
Kuo-Chuin Wong 《Estuaries and Coasts》2002,25(4):519-527
The Chesapeake and Delaware (C&;D) Canal is a man-made waterway connecting two of the largest estuaries on the east coast of the United States: Chesapeake Bay and Delaware Bay. A set of current meter data collected during April–May 1975 along two cross-sections of the C&;D Canal was used to examine the spatial distributions of the currents at tidal and subtidal time scales. The different responses of the Chesapeake and Delaware Bays to tidal and wind forcing produce significant differences in sea level fluctuations between the two ends of the canal. These alongcanal surface slopes produce significant barotropic current fluctuations at both tidal (semidiurnal and diurnal) and subtidal (2-d to 3-d) time scales. Under the influence of bottom friction, the barotropic currents near the surface are stronger than those at depth, but these currents do not exhibit significant lateral variations across the canal. On the other hand, the long-term flow in the canal exhibits strong lateral variability with eastward flow off the south shore of the canal and westward flow off the north shore of the canal. The lateral structure of the long-term flow may carry significant implications for the long-term exchange of material between the two bays. 相似文献
4.
The discharge of taconite tailings into Lake Superior at Silver Bay, Minnesota, produces turbidity current flow. The silty fine-sand tailings fraction transported to the deepest part of the lake has formed a small fan with valleys similar in gross morphology to a submarine fan. Current meters anchored 5 m above the lake floor over the wall and over the levee of a distributary valley on the fan recorded intermittent turbidity current flows during 30 weeks in 1972–73. At least twenty-five discrete periods of observation of turbidity current flow were obtained; single episodes lasted 4?328+ h. Only flows thick enough to overflow the eastern levee of the valley could be observed, and this accounts for the intermittent nature of our observations, as flow within the valleys is expected to be continuous as long as tailings are discharged. Flow velocities were higher near the valley axis where the flow is thicker. Velocities measured over the valley wall averaged 10.8 cm/s for eleven episodes; velocities measured over the levee, more than 1/2 km from the valley axis, only 3.3 cm/s. The maximum velocity during 1300 h of observation did not exceed 31 cm/s. This agrees reasonably well with velocities calculated from channel properties, as commonly done for turbidity currents on deep-sea fans. Current meters tethered above the bottom meters indicate that lake currents normally parallel the shore throughout the water column. With the onset of a turbidity current, currents higher in the water column remain unchanged but velocities near the bottom go to zero, currents then change azimuth by 90° to parallel the downslope (down-valley) direction of the fan, then increase in velocity. During a turbidity current episode, the direction of bottom flow stays relatively constant (± 20° of the down-valley trend) but the velocity oscillates (commonly with 10 cm/s amplitude), periods being of 1/2 h or less to several hours. Turbidity currents generated on Reserve Mining Company's delta are effective in carrying essentially all tailings discharged into the lake into deeper water, where they are deposited. 相似文献
5.
Carbonate environments inhabit the realm of the surface, intermediate and deep currents of the ocean circulation where they produce and continuously deliver material which is potentially deposited into contourite drifts. In the tropical realm, fine‐grained particles produced in shallow water and transported off‐bank by tidal, wind‐driven, and cascading density currents are a major source for transport and deposition by currents. Sediment production is especially high during interglacial times when sea level is high and is greatly reduced during glacial times of sea‐level lowstands. Reduced sedimentation on carbonate contourite drifts leads to early marine cementation and hardened surfaces, which are often reworked when current strength increases. As a result, reworked lithoclasts are a common component in carbonate drifts. In areas of temperate and cool water carbonates, currents are able to flow across carbonate producing areas and incorporate sediment directly to the current. The entrained skeletal carbonate particles have variable bulk density and shapes that lower the prediction of transport rates in energy‐based transport models, as well as prediction of current velocity based on grain size. All types of contourite drifts known in clastic environments are found in carbonate environments, but three additional drift types occur in carbonates because of local sources and current flow diversion in the complicated topography inherent to carbonate systems. The periplatform drift is a carbonate‐specific plastered drift that is nearly exclusively made of periplatform ooze. Its geometry is built by the interaction of along‐slope currents and downslope currents, which deliver sediment from the adjacent shallow‐water carbonate realm to the contour current via a line source. Because the periplatform drift is plastered on the slopes of the platforms it is also subject to mass gravity flow and large slope failures. At platform edges, a special type of patch drift develops. These hemiconal platform‐edge drifts also contain exclusively periplatform ooze but their geometry is controlled by the current around the corner of the platform. At the north‐western end of Little and Great Bahama Bank are platform‐edge drifts that are over 100 km long and up to 600 m thick. A special type of channel‐related drift forms when passages between carbonate buildups or channels within a platform open into deeper water. A current flowing in these channels will entrain material shed from the sediment producing areas. At the channel mouth, the sediment‐charged current deposits its sediment load into the deeper basin. With continuous flow, a submarine delta drift is built that progrades into the deep water. The strongly focused current forming the delta drift, is able to rework coarse skeletal grains and clasts, making this type of carbonate drift the coarsest drift type. 相似文献
6.
海南岛洋浦湾沉积作用研究 总被引：9，自引：0，他引：9
本文对海南岛洋浦湾海域的洋浦湾、新英湾、洋浦深槽及拦门沙浅滩的沉积环境和沉积特征做了描述、讨论，对河流、海岸侵蚀和珊瑚礁生物的３种沉积物来源及数量做了分析计算，得出其总量为９×１０4ｍ３／ａ。根据钻孔柱状样的14Ｃ及210Ｐｂ分析，得出８０００ａＢ．Ｐ．以来沉积速率为０．１～０．２ｃｍ／ａ，近百年来沉积速率为１～２ｃｍ／ａ。 相似文献
7.
Observations of the Mobile Bay, Alabama, plume during a flood event in April 1991 reveal significant differences in the current field on either side of a front associated with the buoyant plume. During a strong southeasterly wind, turbid, low salinity water from Mobile Bay was pushed through an opening in the west side of the ebb-tidal delta and moved parallel to the coast. A stable front developed between the low salinity water of the buoyant plume (11‰) and the high salinity coastal water (>23‰) that was being forced landward by the prevailing winds. Despite the shallow water depth of 6 m, measurements of currents, temperature, and salinity show large shears and density gradients in both the vertical and the horizontal directions. At a station outside of the buoyant plume, currents at 0.5 m and 1.5 m below the surface were in the same direction as the wind. Inside the plume, however, currents at 0.5 m below the surface were parallel to the coast, 45°, off the direction of the wind and the magnitude was 45% larger than the magnitude of the surface currents outside the plume. Beneath the level of the plume, the currents were identical to the wind-driven currents in the ambient water south of the front. Our observations suggest that the wind-driven surface currents of the ambient water converged with the buoyant plume at the front and were subducted beneath the plume. The motion of the ambient coastal surface water was in the direction of the local wind stress, however, the motion of the plume had no northerly component of motion. The plume also did not show any flow toward the front, suggesting a balance between the northerly component of wind stress and the southerly component of buoyant spreading. In addition, the motion of the plume did not appear to affect the motion of the underlying ambient water, suggesting a lack of mixing between the two waters. 相似文献
8.
黑龙洞泉域地下水流数值模拟与预测 总被引：2，自引：0，他引：2
为了对黑龙洞泉域水资源进行评价, 通过对地质条件、水位观测资料的深入研究, 以水均衡原理、地下水渗流理论为基础, 建立了黑龙洞泉域地下水渗流数值模型.以灰色序列预测模型为辅助手段, 结合历年的降水规律, 对未来现状开采条件下的年均降水量、地下水流场、水位及泉流量进行了不同保证率条件下的预测, 若2010年为丰水年(保证率20%)、平水年(保证率50%)、枯水年(保证率75%), 黑龙洞泉汛期地下水位标高分别为超过130m、达到130m、低于130m, 汛期泉流量分别为超过10m3/s、7m3/s、5m3/s.计算结果有利于指导黑龙洞泉域地下水资源的管理和开发利用. 相似文献
9.
Flat-bottomed depression 50–150 m in diameter and 60–80 cm deep occur in the floor of Norton Sound, Bering Sea. These large
erosional bedforms and associated current ripples are found in areas where sediment grain size is 0.063–0.044 mm (4–4.5 φ),
speeds of bottom currents are greatest (20–30 cm/s mean speeds under nonstorm conditions, 70 cm/s during typical storms),
circulation of water is constricted by major topographic shoals (kilometers in scale), and small-scale topographic disruptions,
such as ice gouges, occur locally on slopes of shoals. These local obstructions on shoals appear to disrupt currents, causing
separation of flow and generating eddies that produce large-scale scour. Offshore artificial structures also may disrupt bottom
currents in these same areas and have the potential to generate turbulence and induce extensive scour in the area of disrupted
flow. The size and character of natural scour depressions in areas of ice gouging suggest that large-scale regions of scour
may develop from enlargement of local scour sites around pilings, platforms, or pipelines. Consequently, loss of substrate
support for pipelines and gravity structures is possible during frequent autumn storms. 相似文献
10.
Measurements were made of tidal currents, bed sediment particle sizes, and bedform dimensions at the South Branch and the
South Channel of the Changjiang estuary, China, during the dry season in 1997 and the flood season in 1998. The near bottom
current speed and direction were measured by a mechanical current meter for 10 h in 1997. The near surface current speed and
direction were measured by a Current Meter of Endeco/YSI Inc. 174 SSM for 14 h in 1997 and 1998. Nine bed sediment samples
were taken and their particle sizes were analyzed with sieves and siphons. The bedforms were nautically detected by an echo
sounder and a side scan sonar. Results show that the ebb tides had larger near-bottom and near-surface current speeds and
longer durations than the flood tides, in which the former occurred during the flood season in 1998 and not in the dry season
in 1997. The bed sediments were composed of coarse silts and very fine sands during the dry season but of fine sands during
the flood season. Bedforms were dominated by ebb tidal currents, the height∶length ratios of dunes and lee face angles were
low, and heights and lengths were larger during the flood season in 1998. The ebb and flood tidal currents, bed sediment sizes,
and dune morphology were largely controlled by the seasonal runoff variations. A new tentative boundary might be proposed
for natural dunes in very fine sand with the availability of additional field data in the future. 相似文献
11.
Lisa Ann Levin 《Estuaries and Coasts》1983,6(4):364-371
Surface water transport and larval dispersal potential within Mission Bay, San Diego, California and along the southern California coast were studied with drift test tubes. Drift tubes, released once during each season at six sites inside Mission Bay, traveled up to 173 km north and 205 km south of Mission Bay at maximum rates of 36 cm per s (north) and 50 cm per s (south). These findings were used to estimate probability of larval transport out of Mission Bay for the intertidal spionid polychaete Pseudopolydora paucibranchiata (Okuda) which occurred in the back of the bay. Outer coast drift tube returns were used to determine potential for gene flow, via larval exchange, between populations in isolated bays along the California coast. Drift tube recoveries and larval abundances in the plankton indicate that few Pseudopolydora larvae leave Mission Bay, but that longshore currents can carry those which do to other suitable bay habitats. 相似文献
12.
The dynamics and thermodynamics of the surface layer of the Arabian Sea, north of about 10N, are dominated by the monsoon-related
annual cycle of air-sea fluxes of momentum and heat. The currents in open-sea regime of this layer can be largely accounted
for by Ekman drift and the thermal field is dominated by local heat fluxes. The geostrophic currents in open-sea subsurface
regime also show a seasonal cycle and there is some evidence that signatures of this cycle appear as deep as 1000 m. The forcing
due to Ekman suction is an important mechanism for the geostrophic currents in the central and western parts of the Sea. Recent
studies suggest that the eastern part is strongly influenced by the Rossby waves radiated by the Kelvin waves propagating
along the west coast of India.
The circulation in the coastal region off Oman is driven mainly by local winds and there is no remotely driven western boundary
current. Local wind-driving is also important to the coastal circulation off western India during the southwest monsoon but
not during the northeast monsoon when a strong (approximately 7 × 106m3/sec) current moves poleward against weak winds. This current is driven by a pressure gradient which forms along this coast
during the northeast monsoon due to either thermohaline-forcing or due to the arrival of Kelvin waves from the Bay of Bengal.
The present speculation about flow of bottom water (deeper than about 3500 m) in the Arabian Sea is that it moves northward
and upwells into the layer of North Indian Deep Water (approximately 1500–3500m). It is further speculated that the flow in
this layer consists of a poleward western boundary current and a weak equatorward flow in the interior. It is not known if
there is an annual cycle associated with the deep and the bottom water circulation. 相似文献
13.
In October of 2004, a 3-d observational program to measure flow and sediment resuspension within a coastal intertidal salt
marsh was conducted in the North Inlet/Winyah Bay National Estuarine Research Reserve located near Georgetown, South Carolina.
Current and acoustic backscatter profiles were obtained from a moored acoustic Doppler current profiler (ADCP) deployed in
a shallow tidal channel during the spring phase of the tidal cycle under high discharge conditions. The channel serves as
a conduit between Winyah Bay, a large brackish estuary, and North Inlet, a saline intertidal coastal salt marsh with little
freshwater input. Salinity measurements indicate that the water column is vertically well mixed during flood, but becomes
vertically stratified during early ebb. The stratification results from brackish (15 psu) Winyah Bay water entering North
Inlet via the tidal channel, suggesting an exchange mechanism that permits North Inlet to receive a fraction of the poor water
quality and high discharge flow from upland rivers. Although maximum flood currents exceed maximum ebb currents by 0.2 m s−1, suspended sediment concentrations are highest during the latter ebb phase and persist for a longer fraction of the ebb cycle.
Even though the channel is flood-dominated, the higher concentrations occurring over a longer fraction of the ebb phase indicate
net particulate transport from Winyah Bay to North Inlet during spring tide accompanied by high discharge. Our evidence suggests
that the higher concentrations during ebb result from increased bed friction caused by flow asymmetries and variations in
water depth in which the highest stresses occur near the end of ebb near low water despite stronger maximum currents during
flood. 相似文献
14.
Cap-Tourmente tidal flat is located on the north shore of the St. Lawrence middle estuary, 50 km downstream from Quebec city, Canada. Seasonal variations in sedient accretion were studied during the period without ice from May to December, using horizontal plates in conjunction with vertical stakes. The sedimentological regime which is characterized by very rapid changes, can be divided into four periods. There are two periods of intense erosion in May and October–November; during these months, erosion is initiated by walking and beak probing of very large flocks of snow geese. During the summer, very rapid accretion occurs for approximately 100 days; during this period, the sedimentation rate is 2 mm per day in the lower section of the tidal marsh which is covered with vegetation. Among the numerous factors influencing the sedimentation cycle, the very gradual slope of the upper part of the flat (0.25%) seems to be one of the most important because it results in a very large area (550 m wide) which is protected from strong tidal currents. This latter area is covered with dense and high vegetation which provides an effective protection against erosion unitl the snow geese arrive in October and raze it in a few days. The presence of vegetation reduces the velocities of tidal currents, particularly during ebb and modifies their direction for both flood and ebb, orienting them perpendicularly to the main tidal flow. 相似文献
15.
Kuo-Chuin Wong 《Estuaries and Coasts》1999,22(2):194-205
The buoyant discharge from Delaware Bay forms two separate branches of residual outflow near the bay mouth, one along each shore. Upon exiting the bay, the branch along the Delaware shore turns right to form the southward flowing Delaware coastal current along the inner continental shelf off the Delaware, Maryland, and Virginia coasts. CTD and thermosalinograph, data collected at the mouth of Delaware Bay over two semidiurnal tidal cycles are used to examine the hydrographic distribution at the source region of the Delaware coastal current. In this region the buoyant source water of the coastal current, is largely detached from the shoreline and confined to the top 15 m of the water column over much of the tidal cycles. The core of the coastal current's source water, as defined by the point of salinity minimum, is located over the deep channel well offshore of the Delaware coast. The separation between this buoyant water and the more saline waters right along the Delaware coast and that in the central part of the bay mouth are marked by regions of high horizontal salinity gradients. The horizontal salinity gradients around the inshore and offshore boundaries of the source water of the coastal current are intensified during the flood tide, and clearly defined fronts (with a change of 3‰ over a distance of 150 m) are present at the offshore boundary near the end of the flood tide. The structure of the mean flow and the distribution of the brackish coastal current on the inner continental shelf contribute to the persistence of stratification in the source region off the Delaware shore throughout the ebb and flood tides. In contrast, the ebb-induced stratification in the region off the New Jersey shore is quickly destroyed with the onset of the flood current. 相似文献
16.
长江中游武汉-九江河段河道卡口及其阻洪可能效应探讨 总被引：8，自引：0，他引：8
探讨了长江中游武汉九江河段河道卡口的地质地貌方面特征,并通过对历史水文数据的分析研究了中游河道卡口对洪水的阻碍作用。并以田家镇卡口为典型案例,利用研究河段的水文资料,分析了中游河道卡口对洪水排泄的阻碍作用;如若实施田家镇扩卡,将对中游的防洪是有利的,而且会大大减轻中游特别是武汉的防洪压力,但有可能对下游河势的稳定、河床演变等造成影响,并可能造成其它环境影响,尚需进一步研究。当前全球变暖、水循环加剧、长江中游降水增多,长江中下游将面临更大防洪压力,通过长江中下游扩卡增泄,以适应当前全球变暖的影响。 相似文献
17.
强火山活动是气候变化的重要自然驱动因素,可导致中国降水出现年际或年代际变化,甚至极端的旱涝现象。探究位于中国邻域的印度尼西亚—菲律宾一带的强火山喷发与中国旱涝分布格局的关系,有助于阐释中国旱涝发生的时空规律及机制,为预测未来火山爆发可能导致的降水异常提供借鉴。本文基于1500—2000年期间世界强火山活动和中国旱涝资料,运用时序叠加分析的方法辨识了印度尼西亚—菲律宾一带的强火山喷发后中国旱涝在年际尺度上的时空变化特征,并对1815年Tambora火山喷发进行案例分析。结果表明印度尼西亚—菲律宾一带的强火山喷发对中国的旱涝格局有一定的影响:强火山喷发后第0年至第2年,中国中东部各站点的整体变化为偏涝;在第3年,整体出现了偏旱的转变,且变化幅度相比其他年份较大;就地区而言,喷发后华北、华南地区分别出现了由旱转涝、由涝转旱的变化,并且这些变化大概持续了2~3年,随后2个区域均恢复了喷发前的旱涝趋势;印度尼西亚1815年Tambora火山喷发后0~3年,中国以涝情为主,但发生涝情的区域逐年在发生变化。 相似文献
18.
Information on reflected surface gravity waves from the shoreline is required for understanding the coastal hydrodynamics. We have quantified the reflected swells (frequency band 0.045–0.12 Hz) from the west and east coast of India based on the spectral wave data derived from the directional waverider buoys. Reflection coefficient, ratio of the reflected and incident spectral energy, was used to quantify the reflected waves. Influence of the seasons, cyclone, relative depth, land/sea breeze, tides and tidal current on the reflected waves were examined. For the locations off the west coast of India, seasons have large impact on the reflection coefficient and were relatively less during the monsoon season due to the increase in incident wave energy. Locations off the east coast of India show almost the same reflection coefficient throughout the year and have no significant seasonal variations. The reflection coefficient off Puducherry was higher than that for other locations due to the low incident wave energy. The reflection coefficient was low during the cyclone period, but the reflected energy during cyclone was higher than that during the normal condition due to the high incident wave energy. High-energy reflected waves show large variation with tide due to the trapping and dissipation of reflected wave by bottom friction and this effect cause low reflection in deep water location than shallow water location. The reflection coefficient decreases with increase in relative depth off west coast of India. 相似文献
19.
Speed and direction of bottom currents induced by density underflow of two sediment-laden rivers were measured by oceanographic current meters in the Walensee (= Lake of Walenstadt), Switzerland. The apparently shooting flow of currents (up to 30 cm/s in this study) is suggested as an explanation for laminations in turbidite sequences. The current speed apparently stabilizes on slopes around 2°; this angle seems to correspond to the critical slope where the flow of the measured currents becomes steady. Current direction is controlled by bottom topography and direction of river inflow. Reversal of current direction observed at two sites is probably due to the underflow-induced backward motion of the overlying lake water. Underflow activity in Walensee is correlative with density peaks of the river water input. The currents are compared to Lake Mead (Southwestern U.S.) underflows and sporadic currents in some submarine canyons. 相似文献
20.
《China Geology》2019,2(3):325-332
Based on the 39 surface sediment samples collected in the flood season and the dry season in 2012 respectively and the measured hydrological data in October 2012, the sediment grain size characteristics has been analyzed and the response mechanism of surface sediments to estuarine hydrodynamics was revealed by calculating the range of waves and tidal currents. The results show that: (1) The grain size of the surface sediment samples decreased gradually from land to sea in the flood season. The fine sediment was redistributed under marine hydrodynamics in the dry season and the sediments showed coarser tendency ingeneral; (2) tidal current stirring sediment was very obvious in Dagu River estuary area, and wave stirring sediments mainly occurred in the tidal flat area and estuary sand bar area; (3) in the flood season, surface sediment sat the estuary were transported towards south and southeast. In the dry season, surface sediments were transported towards southwest at the north area of Jiaozhou Bay Bridge, and sediments were transported towards northeast area at the south of Jiaozhou Bay Bridge. 相似文献